This invention relates to a mechanical actuating and automatic adjustment mechanism for use in a heavy duty disc brake.
Until now, most disc brakes have been hydraulically actuated and have been used mainly in passenger cars and light trucks. However, because of Government safety regulations and the inherent advantages of disc brakes, heavy duty air braked vehicles are expected to be equipped with air actuated disc brakes in the near future. Since air actuated disc brakes normally incorporate some type of mechanical actuator to transmit and multiply actuation forces generated by the air pressure actuator so that the friction elements used in the disc brake may be urged into braking engagement with the rotor with sufficient force to effort a brake application, and since these mechanical actuators normally have a very limited stroke, it is necessary to provide automatic adjustment mechanisms which effect a brake adjustment to limit reaction of the friction elements to a predetermined amount which is always within the stroke capabilities of the mechanical actuator. In actuators incorporating a wedge actuating mechanism of the type disclosed herein, it is critical that the wedges used in the wedge actuator be maintained in alignment. For this reason, prior art actuators required a fairly complicated manufacturing process to ensure alignment of the wedges and to prevent relative rotation of one of the wedges with respect to the housing.